Method and circuit for energizing an electrical device

ABSTRACT

A method and a circuit for energizing an electrical device are described.

BACKGROUND OF THE INVENTION

The present invention relates to a method and a circuit for energizingan electrical device, as well as a system, a mobile device, and a powersupply device using the method and the circuit for energizing anelectrical device.

BRIEF SUMMARY OF THE INVENTION

According to an embodiment of the present invention, a method forenergizing an electrical device is provided. The electrical device iscoupled via a switch to an electrical power supply. According to themethod, electrical energy is generated by converting energy of amechanical movement into electrical energy. The generated electricalenergy is supplied to the switch to provide an electrical coupling ofthe electrical device to the electrical power supply. The switch may bea semiconductor switch, for example a thyristor, a MOSFET, an IGBT orthe like, or a mechanical switch, for example a relais. The electricaldevice may be a charger for charging a further electrical device, forexample a battery powered mobile device. The charger and the batterypowered device may be detachably connectable with each other via a plugand a matching socket. In this case, the electrical energy foractivating the switch may be generated by the mechanical movement ofinserting the plug into the socket. Furthermore, the electrical devicemay be a power supply unit for supplying the further device withelectrical energy from the electrical power supply.

In the field of consumer electronics, especially battery powered mobiledevices like for example mobile phones, mobile personal digitalassistants, mobile audio playback devices like MP3 players, and mobilecomputers, the mobile device is coupled to the electrical power supplyvia a charger or a power supply unit. The charger or the power supplyunit is on one side detachably connected to the battery powered mobiledevice via a connector comprising a plug and a matching socket, and onthe other side via another connector to the electrical power supply, theso-called mains. Many users of such consumer electronics leave thecharger or power supply unit connected to the electrical power supply,when they disconnect the mobile battery powered device from the chargeror power supply unit. However, even when the connection between themobile or battery powered device to the charger or power supply unit isdisconnected, the charger or the power supply unit still consumeelectrical energy from the electrical power supply as long as it is areelectrically connected to the electrical power supply.

Therefore, according to an embodiment of the present invention, thecharger or the power supply unit is coupled to the electrical powersupply via a switch which is adapted to couple and decouple the chargeror the power supply unit electrically to/from the electrical powersupply. A decoupling may be initiated by sensing a disconnecting of themobile battery powered device from the charger or the power supply unit.For initiating an initial coupling of the charger or the power supplyunit to the electrical power supply, the switch has to be activated,thus energizing the charger or the power supply unit with electricalenergy from the electrical power supply. Therefore, according to anembodiment of the present invention, electrical energy is generated byconverting a mechanical movement into electrical energy, and thiselectrical energy is provided to the switch. After the charger or thepower supply unit has been energized, the switch may then be held in theactivated state with electrical energy being derived from the charger orthe power supply unit from the electrical power supply. Thus, thecharger or the power supply unit consumes electrical energy only whenthe mobile battery powered device is connected.

According to an embodiment of the present invention, a piezoelectricelement is used for generating electric energy from a mechanicalmovement by using the piezoelectric effect. Possible materials for thepiezoelectric element include piezoelectric plastics and piezoelectricceramics, for example. Therefore, the piezoelectric element may beintegrated into a connector connecting the electrical device like thecharger or the power supply unit to the further electrical device likethe mobile battery powered device. Thus, when connecting the electricaldevice with the further device by moving the plug into the matchingsocket, the piezoelectric element may be mechanically activated togenerate the electrical energy being supplied to the switch.

According to another embodiment, the generated electrical energy isgalvanically isolated from the switch. This helps to separate lowervoltages on a secondary side of the electrical device from highervoltages of a primary side of electrical device, to keep hazardousvoltages away from the user.

According to another embodiment, the generated electrical energy isstored before being supplied to the switch. When using for example apiezoelectric element for generating the electrical energy, thepiezoelectric element may generate a short peak of high energeticelectrical energy. This peak may be too short for energizing theelectrical device long enough to get the electrical device started up,and therefore it may be advantageous to store this electrical energy forexample in a capacitor intermediately and provide it for a longer timefrom the capacitor to the switch until the electrical device is startedup. Furthermore, the generated electrical energy may be limited to apredefined range, to avoid voltage peaks which may be dangerous for theelectrical device, the further electrical device or user.

According to another embodiment of the present invention a circuit forenergizing an electrical device is provided. The circuit comprises aswitch, a converter, and a control circuit. The switch is adapted tocouple the electrical device to an electrical power supply. Theconverter is adapted to generate electrical energy by converting energyof a mechanical movement into electrical energy. The control circuit iscoupled to the switch and the converter and is furthermore adapted tosupply the generated electrical energy from the converter to the switch,wherein the switch upon receiving the generated electrical energyprovides an electrical coupling of the electrical device to theelectrical power supply. The converter for generating electrical energyfrom a mechanical movement may be a piezoelectric element utilizing thepiezoelectric effect for generating the electrical energy from themechanical movement. The electrical device may comprise a charger forcharging a further device or a power supply unit for supplying thefurther device with electrical energy from the electrical power supply.The electrical device may be detachably connectable to the furtherdevice via a connector comprising a plug and a matching socket. Theconverter, for example the piezoelectric element, may be integrated intothe connector such that the generated electrical energy is generated bythe mechanical movement when the plug is inserted into the socket.

The further device may comprise a battery powered device which cannot beconnected directly to the high voltage of the electrical power supply,but needs to be supplied by a lower voltage derived from the electricalpower supply by the electrical device, for example the charger or thepower supply unit. The battery powered device may be a mobile device, amobile phone, a personal digital assistant, a mobile navigation systemor a mobile computer.

According to another embodiment the control circuit is further connectedto the electrical device and configured to supply electrical energy fromthe electrical device to the switch after the mechanically generatedelectrical energy was supplied to the switch. Thus, the electricalcoupling of the electrical device to the electrical power supply ismaintained even when after the mechanical movement the converter doesnot provide further electrical energy to the switch.

According to another embodiment, the control circuit comprises atransformer for galvanically isolating the electrical energy generatedby the converter from the switch. Furthermore, the control circuit maycomprise a capacitor for storing the generated electrical energy beforeit is supplied to the switch. Finally, the control circuit may comprisea voltage limiting arrangement like a Zener diode, a breakdown diode, alow pass filter or a voltage regulator etc. for limiting the voltage ofthe electrical energy generated by the converter to a predefined range.

According to another embodiment of the present invention a systemcomprising a first electrical device, a second electrical device, aswitch, a connector, a converter and a control circuit is provided. Thefirst electrical device, for example a charger or a power supply unit,is configured to adapt electrical energy from an electrical powersupply, a so-called mains, to electrical requirements of the secondelectrical device, for example a mobile device, a battery powereddevice, a mobile phone, a personal digital assistant, a mobilenavigation system or a mobile computer. The switch is adapted to couplethe first electrical device to the electrical power supply and maycomprise a thyristor, a MOSFET or an IGBT. The connector is adapted todetachably connect the first electrical device to the second electricaldevice. The connector comprises a plug and a matching socket. Accordingto a preferred embodiment, the connector is a USB connector. Theconverter is adapted to generate electrical energy by converting amechanical movement into electrical energy. The converter is integratedinto the connector such that the generated electrical energy isgenerated by a mechanical movement of the plug being inserted into thesocket. The control circuit is coupled to the switch and the converter.The control circuit is adapted to supply the generated electrical energyfrom the converter to the switch to enable the switch to provide anelectrical coupling of the first electrical device to the electricalpower supply.

The system may further comprise an energy supply line for supplyingenergy from the first electrical device to the second electrical device.The energy supply line may be a multiple-conductor line or cable whichis on one end of the line fixedly connected to the first electricaldevice and provides for example a plug on the other end, wherein theplug is matching to a socket provided in the second electrical device.The generated electrical energy, which may be generated by moving theplug into the socket, is transmitted from the converter to the controlcircuit via the energy supply line.

According to another embodiment of the present invention a mobile deviceis provided which comprises a first part of a connector for detachablyconnecting an electrical device, for example a charger or a power supplyunit, to the mobile device. The electrical device comprises a secondpart of the connector which is matching to the first part comprised inthe mobile device. The mobile device comprises furthermore a converteradapted to generate electrical energy by converting energy of amechanical movement into electrical energy. The converter is integratedinto the first part of the connector such that the generated electricalenergy is generated by the mechanical movement which occurs when thefirst part of the connector is connected to the second part of theconnector, for example when the first part is inserted into the secondpart or vice versa.

The mobile device may be a battery powered device, for example a mobilephone, a personal digital assistant, a mobile navigation system or amobile computer.

According to yet another embodiment of the present invention, a powersupply device is provided. The power supply device comprises a powerconverter, a switch, a first part of a connector, a converter, and acontrol circuit coupled to the switch and the converter. The powerconverter is adapted to convert electrical energy from an electricalpower supply, a so-called mains, to electrical requirements of a furtherelectrical device which is connectable to the first part of theconnector. In general, this conversion comprises a conversion ofelectrical energy with a high voltage, for example 110 V or 220 V, toelectrical energy with a lower voltage, typically in the range of 5-25V. However, a power converter is not restricted to such a downscaling ofthe voltage and may also provide an upscaling of the voltage, forexample to convert 12 V from an electrical power supply of a vehicle tothe electrical requirements of the further electrical device. The switchis adapted to couple the power converter to the electrical power supplyand may comprise a semiconductor switch, for example a thyristor, atriac, a MOSFET, or an IGBT. The first part of the connector may be aplug or a socket for detachably connecting the power supplied device tothe further electrical device, wherein the further electrical devicecomprises a second part of the connector, for example a socket or a plugmatching to the first part. The converter is adapted to generateelectrical energy by converting energy of a mechanical movement intoelectrical energy. The converter is integrated into the connector suchthat the generated electrical energy is generated by the mechanicalmovement when the first part of the connector and the second part of theconnector are connected. The control circuit as adapted to supply theelectrical energy generated from the converter to the switch to providean electrical coupling of the power converter to the electrical powersupply.

The power supply device may be a charger for charging the furtherelectrical device. The converter for generating the generated electricalenergy from the mechanical movement may be integrated in the first partof the connector or may be alternatively integrated in the second partof the connector.

Although specific features described in the above summary and thefollowing detailed description are described in connection with specificembodiments, it is to be understood that the features of the embodimentsdescribed can be combined with each other, unless it is noted otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereinafter exemplary embodiments of the invention will be describedwith reference to the drawings.

FIG. 1 shows a block diagram of a system according to an embodiment ofthe present invention.

FIG. 2 shows an embodiment of a switch according to an embodiment of thepresent invention in more detail.

FIG. 3 shows an embodiment of a control circuit according to anembodiment of the present invention.

FIG. 4 shows another embodiment of a system according to an embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following, exemplary embodiments of the present invention will bedescribed in detail. It is to be understood that the followingdescription is given only for the purpose of illustrating the principlesof the invention and it is not to be taken in a limiting sense. Rather,the scope of the invention is defined only by the appended claims and isnot intended to be limited by the exemplary embodiments hereinafter.

It is to be understood that in the following detailed description of theexemplary embodiments, any direct connection or coupling betweenfunctional blocks, devices, components or other physical or functionalunits shown in the drawings or description herein could also beimplemented by an indirect connection or coupling. The use of samereference numbers in different instances in the description and thefigures may indicate similar or identical items.

It is further to be understood that the features of the variousexemplary embodiments described herein may be combined with each otherunless specifically noted otherwise.

FIG. 1 shows an embodiment of a system 100 according to the presentinvention. The system 100 comprises a charger 101 and a mobile device102, for example a mobile phone. The charger 101 comprises a primaryswitched battery charger 103, a control circuit 104, a two-waysemiconductor switch 106, a current sensing resistor 107 and a chargingconnector 108. The primary switched battery charger 103 is connectablevia lines 109 and 110 to an electrical power supply, a so-called mains,providing for example 110 V or 220 V.

In the line 110 the semiconductor switch 106 is inserted such that, whenthe switch 106 is in the disconnected state, the primary switchedbattery charger 103 is electrically completely disconnected from theelectrical power supply and no current is flowing through lines 109 and110. When the semiconductor switch 106 is in the connected state, theprimary switched battery charger 103 is connected to and supplied withenergy from the electrical power supply via lines 109 and 110.

The primary switched battery charger 103 is adapted to convert a highvoltage supplied from the electrical power supply into a low voltagewhich is suitable for charging a battery of the mobile device 102. Whenthe primary switched battery charger 103 is connected on its primaryside via lines 109 and 110 to the electrical power supply, the primaryswitched battery charger 103 provides on its secondary side via lines111 and 112 the lower voltage. The lines 111 and 112 connect thesecondary side of the primary switched battery charger 103 with thecharging connector 108. The charging connector 108 may be a plug whichfits into a corresponding socket in the mobile device 102.

As shown in FIG. 1, in line 112 a series resistor R 107 is insertedwhich is used as a current sensing resistor which provides a currentsensing voltage on lines 113 and 114 as long as a current is flowingthrough line 112 and the resistor 107. Therefore, when the mobile device102 is connected via the charging connector 108 to the primary switchedbattery charger 103, and the primary switched battery charger 103 isconnected via lines 109 and 110 to the electrical power supply, acharging voltage will be present on lines 111 and 112 and acorresponding charging current will flow through lines 111 and 112causing a hold voltage on lines 113 and 114.

The charging voltage on lines 111 and 112 is additionally supplied vialines 115 and 113, respectively, to the control circuit 104, andadditionally the hold voltage on lines 113 and 114 is supplied to thecontrol circuit 104. As long as the charging voltage and the holdvoltage are present, the control circuit 104 activates the semiconductorswitch 106 via a connection 116 between the control circuit 104 and thesemiconductor switch 106 to keep the semiconductor switch 106 in theconnected state. When the charging connector 108 is removed from themobile device 102, i.e. the plug of the charging detector 108 is pulledout of the socket of the mobile device 102, the current flow through thelines 111 and 112 is stopped. Thus, the hold voltage on the lines 113and 114 becomes zero and the control circuit 104 causes thesemiconductor switch 106 via the connection 116 to change into thedisconnected state. Because of this there is no current flow through thelines 109 and 110 from the electrical power supply to the batterycharger 103 and thus the battery charger 103 does not consume any energyfrom the electrical power supply anymore.

However, when the charging connector 108 is reconnected to the mobiledevice 102, the charger 101 has to be reenergized to provide thecharging voltage for the mobile device 102. This is accomplished bygenerating electrical energy by converting mechanical energy intoelectrical energy. The mechanical energy is induced by the insertion ofthe charging connector 108 into the socket of the mobile device 102, asindicated by a force arrow F in FIG. 1. To accomplish this, the chargingconnector 108 comprises a piezoelectric element 117 and a springsuspended hammer 118. The piezoelectric element 117 is for example apiezoelectric ceramic or a piezoelectric plastic. The piezoelectricelement 117 works in a similar way as a piezoelectric gas lighter, butusing much lower force and much lower voltage. The spring suspendedhammer 118 is released when the charging connector 108 is plugged intothe mobile device 102. The hammer 118 hits the piezoelectric element 117thus generating a transient voltage as a starting voltage on lines 119and 120. When the charging connector plug 108 is unplugged from themobile device socket 102, the spring of the spring suspended hammer 118is returned to its initial state.

Thus, the piezoelectric element 117 is excited by an impact from thespring suspended hammer mechanism 118, and the transient startingvoltage is provided to the control circuit 104. This starting voltage isfed from the control circuit 104 via the connection 116 to thesemiconductor switch 106. The energy needed to trigger the semiconductorswitch 106 is low and the energy provided by the piezoelectric element117 is sufficient to energize the semiconductor switch 106 for such along time that the primary switched battery charger 103 gets started upand provides the charging voltage to the mobile device 102 and thus thehold voltage on lines 113 and 114 for keeping the switch 106 via thecontrol circuit 104 in the conducting state even when there is no moreenergy from the piezoelectric element 117.

The two way semiconductor switch 106 may be composed of a triac asindicated in FIG. 1 or may be composed of two MOSFETs in series asindicated in FIG. 2, or may be composed of IGBTs in series (not shown)or of any other suitable kind of semiconductor switch.

If there is a demand of a galvanic isolation, a transformer 122 can beused for coupling the transient voltage from the piezoelectric element117, as indicated in FIG. 3. The transient voltage or starting voltagefrom the piezoelectric element 117 (FIG. 1) is supplied to a firstwinding 123 of the transformer 122. This starting voltage induces in asecond winding 124 of the transformer 122 a voltage which isintermediately stored in a capacitor 121 and provided via the connection116 to a gate or control input of the semiconductor switch 106. Thecapacitor 121 is optional. The capacitor 121 increases the time thestarting voltage is supplied to the semiconductor switch 106 when thelengths of the transient voltage of the starting voltage is too short tostart up the primary switched battery charger 103. As indicated in FIG.3, also the hold voltage on lines 113 and 114 can be galvanicallyisolated from the primary side of the primary switched battery charger103. The hold voltage provided on lines 113 and 114 is converted by avoltage to frequency converter 126 into an alternating current (AC).This alternating current is supplied to a third winding 125 of thetransformer 122 and induces a hold voltage in the second winding 124 ofthe transformer 122. This hold voltage is provided to the semiconductorswitch 106 via the connection 116 as indicated in FIG. 1.

FIG. 4 shows another embodiment of a system 100 comprising a charger 101and a mobile phone 102. Similar reference signs in FIGS. 1 and 4indicate similar components and a detailed description of the componentsalready described in connection with FIG. 1 is therefore omitted.

The connection between the charger and the mobile phone 102 in FIG. 4 isaccomplished by a so-called USB connector 108, and, as this USBconnector 108 is a standardized component, in this embodiment thepiezoelectric element 117 and the spring suspended hammer mechanism 118are not integrated into the USB connector 108, but integrated into themobile phone 102. As the standardized USB connector does not provideadditional ports and lines for transmitting the starting voltage, forexample lines 119 and 120 of FIG. 1, the transient voltage from thepiezoelectric element 117 is overlaid on voltage lines 111 and 112 whichare used for charging the battery of the mobile phone 102. As indicatedin FIG. 4, the feeding point from the piezoelectric element 117 can beequipped with a transient protection like a Zener diode 127 or a lowpass filter (not shown) making sure that a too high voltage is notoutput on the lines 111 and 112.

As stated above, the piezoelectric element 117 and the spring suspendedhammer mechanism 118 are integrated into the mobile phone 102. Thespring suspended hammer is released when the USB connector 108 isinserted into the mobile phone 102 providing a force F on the hammer.The hammer hits the piezoelectric element 117 and causes thepiezoelectric element 117 to generate a transient voltage which issupplied via the lines 111 and 112 to the first winding 123 of thetransformer 122. The transient voltage from the piezoelectric element117 induces in the second winding 124 of the transformer 122 a startingvoltage which is supplied via the connection 116 to the semiconductorswitch 106, as indicated in FIG. 1. When the connector 108 is unpluggedfrom the mobile phone 102 the spring of the spring suspended hammermechanism 118 is returned to its initial state. As the piezoelectricmaterial of the piezoelectric element 117 is purely capacitive (e.g. inthe range of 100 pF to 1 nF) this will not affect the normal voltageprovided on lines 111 and 112 for charging the battery of the mobilephone 102. To protect the primary switched battery charger 103 from thetransient voltage of the piezoelectric element 117 a diode 128 may becoupled in series to line 111.

To sum up, when the piezoelectric element 117 is excited by an impact Ffrom the mechanism 118, a voltage transient is generated as a startingvoltage. This starting voltage is fed to the semiconductor switch 106.Therefore, no extra voltage for triggering the semiconductor switch 106is needed. Once the switch 106 is triggered, the switch 106 will conductand the primary switched charger 103 will start and supply voltage tothe mobile device or mobile phone 102. As long as current is flowing tothe mobile device or mobile phone 102 the hold voltage will ensure thatthe semiconductor switch 106 will be in the conducting state. When themobile device or mobile phone 102 is decoupled from the charger 101, thehold voltage will break down and the switch 106 will be in anon-conductive state. In this state no current or leak current existsand therefore the charger 101 does not consume any energy in this state.

While exemplary embodiments have been described above, variousmodifications may be implemented in other embodiments.

For example, the semiconductor switch 106 may be supplied directly fromthe piezoelectric element 117, without using the transformer 122.Furthermore, for example, the hold voltage may be derived in a differentmanner from the primary switch battery charger 103.

Furthermore, the embodiments described above may not only be used in amobile phone, but may be used in any other kind of mobile device orbattery powered device being supplied by a separate battery charger or aseparate power supply unit which is connected to the device via aconnector. It is also understood that all the embodiments describedabove are considered to be comprised by the present invention as it isdefined by the appended claims.

1-26. (canceled)
 27. A mobile device comprising: a first part of aconnector for detachably connecting an electrical device to the mobiledevice, the electrical device comprising a second part of the connector,the second part matching the first part, and a converter adapted togenerate electrical energy by converting energy of a mechanical movementinto electrical energy, the converter being integrated into the firstpart of the connector such that the generated electrical energy isgenerated by the mechanical movement occurring when the first part andthe second part are connected.
 28. The mobile device according to claim27, wherein the electrical device comprises a charger for charging themobile device.
 29. The mobile device according to claim 27, wherein themobile device comprises a battery powered device selected from the groupcomprising a mobile device, mobile phone, a personal digital assistant,a mobile navigation system, and a mobile computer.
 30. A power supplydevice, comprising: a power converter for adapting electrical energyfrom an electrical power supply to electrical requirements of anelectrical device, a switch adapted to couple the power converter to theelectrical power supply, a first part of a connector for detachablyconnecting the power supply device to the electrical device, theelectrical device comprising a second part of the connector matching tothe first part, a converter adapted to generate electrical energy byconverting energy of a mechanical movement into electrical energy, theconverter being integrated into the connector such that the generatedelectrical energy is generated by the mechanical movement occurring whenthe first part and the second part are connected, and a control circuitcoupled to the switch and the converter, wherein the control circuit isadapted to supply the generated electrical energy from the converter tothe switch to provide an electrical coupling of the power converter tothe electrical power supply.
 31. The power supply device according toclaim 30, wherein the power supply device comprises a charger forcharging the electrical device.
 32. The power supply device according toclaim 30, wherein the converter is integrated in the first part of theconnector.
 33. The power supply device according to claim 30, whereinthe converter is integrated in the second part of the connector.